Elution Systems for Treatment of Subterranean Reservoirs

The invention relates generally to elution systems for treating subterranean reservoirs.

Hydrocarbon (oil and gas) recovery requires a plethora of equipment to complete the safe and efficient recovery of fluid produced from a subterranean reservoir, including transfer of the produced fluid to the surface of the earth for processing and refinement to provide one or more useful hydrocarbon products. Primary components in a “completion string” for an oil or gas well include the well casing, which is inserted into a wellbore of a subterranean reservoir to stabilize the well annulus and promote a flow of produced fluid therein; production tubing, which is the main conduit for fluids produced from the reservoir and flowing into the wellbore annulus to reach the earth's surface; and associated conduits and flow controls between the production tubing and a processing and refinement area where the produced fluid is processed and refined to result in one or more useful hydrocarbon products. Additional completion components include packers, downhole gauges, and the like; landing nipples, which are short sections of heavy wall pipe or tubing placed along the completion string to allow for well testing, installation of flow-control devices such as plugs and chokes, and/or interventions to be carried out safely; and the so-called “Christmas tree”, which is an assembly of valves, pressure gauges, spools, and chokes located at the wellhead (the end of the wellbore located at the earth's surface). The Christmas tree conducts fluid emanating from the wellhead via the production tubing toward the processing and refinement area where processing and refining of one or more hydrocarbon products is carried out.

The extraction of oil and gas is intrinsically associated with produced fluid emanating from the subterranean reservoir. The produced fluid enters the wellbore from the reservoir with sufficient force to cause a flow thereof to reach a point at or above the surface of the earth, further as directed by the production tubing. Produced fluids include mixtures of water, hydrocarbons, and other compounds and/or solid materials dissolved, dispersed, or entrained therein. Produced fluids typically include one or more compounds that are corrosive to the well completion components as well as downstream processing equipment. Conditions of produced fluid temperature, pH, presence and concentration of corrodents such as chlorides, HS, and COdetermine the extent of adverse effects on the material performance of equipment components contacted by produced fluid during recovery and processing thereof.

Nearly all operators in the hydrocarbon extraction and processing industry employ corrosion inhibitors to reduce internal corrosion in metal containments, conduits, and other components that are contacted by produced fluids containing corrodents. Corrosion inhibitors are added to the liquids and dissolved gasses which come into contact with metal surfaces in the completion string and processing and refinement equipment, where they act to prevent, retard, delay, reverse, and/or otherwise inhibit the corrosion of metal surfaces, such as carbon-steel metal surfaces. Such use of corrosion inhibitors is recognized to be highly beneficial for extending equipment lifetime. In some cases, effective use of corrosion inhibitors may enable the operator to use carbon steel components in place of expensive high nickel, cobalt, and chromium alloys or other materials.

Corrosion inhibitors in the oil and gas industry are sold in a range of formats, including in liquid forms such as neat liquids and concentrated or dilute solutions, dispersions, or emulsions; in semisolid forms such as gels; in solid forms such as pellets or tablets that are applied to the reservoir to dissolve downhole; in encapsulated forms such as a liquid, gel, or tablet encapsulated (surrounded) by polymer coating; or another composite format including one or more corrosion inhibitors and one or more other materials. The corrosion inhibitors are effective to inhibit corrosion within the well completion string as well as the downstream processing and refinement equipment (collectively, hydrocarbon recovery and processing equipment) when applied at a sufficient concentration in a produced fluid entering hydrocarbon recovery and processing equipment, or when applied to provide a sufficient passivation layer or coating layer on the surfaces of the hydrocarbon recovery and processing equipment.

However, the ability to inject or otherwise provide effective treatments to the interior surfaces of hydrocarbon recovery and processing equipment, in particular to the completion string of a producing wellbore, is a challenge that has not been well-addressed by the industry. In some cases, the infrastructure of the wellbore is appended with one or more means of applying a coating to one or more interior surfaces of the completion string, such as pigging, which is expensive, requires bespoke configuration, and often requires a period of shutdown to clean out one or more parts of a completion string before a fresh coating of polymer or passivation compound can be applied thereto. More commonly, corrosion inhibitors are periodically applied batchwise to a producing wellbore, in amounts empirically based on well production volume. This method does not always result in effective inhibition of corrosion for the entire period between batch treatments, since efficacy trails off over time as fluid concentration decreases and/or surface coatings degrade. Further, batch treatment is inefficient because of the need to transport both the treatment material and equipment to inject the treatment material to the site of the wellbore for each treatment, usually by truck. Further, each batch treatment requires a large volume of adjuvant water, such as about 350 liters to about 600 liters (about to 95 gallons to about 160 gallons) per batch, to dilute and flush the batch into the wellbore and provide effective distribution of the treatment material to the produced fluid, or to the interior surfaces of the hydrocarbon recovery and processing equipment, or both. The adjuvant water must be transported to the treatment site along with the treatment material and injection equipment.

Accordingly, there is an ongoing need in the oil and gas extraction industry for methods, apparatuses, and systems for applying treatments, such as corrosion inhibition treatments, to the surfaces of hydrocarbon recovery and processing equipment that are contacted with produced fluid with greater efficiency than provided by batch treatment; with increased case of use of methods and apparatuses for applying the treatments; and without the equipment cost and periodic downtime required by automated on-board application equipment such as pigs.

Disclosed herein are first passive elution systems including an elution device defining an interior volume having an outlet therefrom, the outlet situated at or near the bottom of the elution device, where the interior volume includes a treatment material; and a conduit in fluid communication with the outlet and arranged and adapted to receive a produced fluid flow from a wellbore of a subterranean reservoir at a location above the surface of the earth, direct the produced fluid flow to provide an eluting contact with the treatment material to form a treated produced fluid flow, and direct the treated produced fluid flow into the wellbore.

In embodiments, the elution device of the first passive elution system is situated on or above the surface of the earth.

In embodiments, the treated produced fluid flow of the first passive elution system is directed into the wellbore at a location at or below the surface of the earth.

In embodiments, the produced fluid flow received from the wellbore by the first passive elution system is a side stream of a production tube.

In embodiments, the first passive elution system excludes external or applied sources of power to receive the produced fluid flow, direct the produced fluid flow to provide the eluting contact with the treatment material, or direct the treated produced fluid flow into the wellbore.

In embodiments, the treatment material of the first passive elution system is a treatment solid, for example a composite treatment solid. In embodiments, the composite treatment solid is a polymer pouch enclosing a treatment liquid, wherein the polymer is water soluble.

In embodiments, the elution device of the first passive elution system excludes an inlet.

In embodiments, the first passive elution system includes a valve disposed between the elution device outlet and the conduit.

In embodiments, the first passive elution system further includes a basket disposed between the elution device outlet and the conduit.

Also disclosed herein are second passive elution systems including an elution device defining an interior volume having an inlet and an outlet, where the inlet is situated on or near the top of the elution device during operation of the passive elution system, and the outlet is situated on or near to the bottom of the elution device during operation of the passive elution system, and wherein the interior volume includes a treatment material; a first conduit in fluid communication with the inlet and arranged and adapted to receive a produced fluid flow from a wellbore of a subterranean reservoir at a location above the surface of the earth, and direct the produced fluid flow through the inlet to provide an eluting contact with the treatment material to form a treated produced fluid; and a second conduit in fluid communication with the outlet and arranged and adapted to receive the treated produced fluid and direct the treated produced fluid into the wellbore.

In embodiments, the elution device of the second passive elution system is situated on or above the surface of the earth.

In embodiments of the second passive elution system, the treated produced fluid flow is directed into the wellbore at a location at or below the surface of the earth.

In embodiments of the second passive elution system, the produced fluid flow received from the wellbore is a side stream of a production tube.

In embodiments the second passive elution system excludes external or applied sources of power to receive the produced fluid flow, direct the produced fluid flow to provide the eluting contact with the treatment material, or direct the treated produced fluid flow into the wellbore.

In embodiments of the second passive elution system, the treatment material is a treatment solid or a composite treatment solid. In some such embodiments, the composite treatment solid is a polymer pouch enclosing a treatment liquid, wherein the polymer is water soluble.

In embodiments the second passive elution system further comprises a float valve operably disposed in the interior volume of the elution device to stop the flow of produced through the inlet; and an outlet valve disposed between the outlet and the second conduit.

Also disclosed herein are methods of treating a wellbore of a subterranean reservoir, the methods including: obtaining a side stream flow of a produced fluid from a production tube of the wellbore, at a location above the surface of the earth; directing an eluting contact of the side stream flow of produced fluid with a treatment material to form a side stream flow of treated produced fluid; and directing the side stream flow of treated produced fluid into the wellbore at a location at or below the surface of the earth.

In embodiments the treating is continuous treating.

In embodiments the treating is batch treating. In some such embodiments, the batch treating is provided by continuous eluting contact of produced fluid with the treatment material.

In embodiments, the side stream flow of produced fluid is obtained at a flow rate of about 1 liter per hour to 10 liters per second. In other embodiments, the side stream flow rate of produced fluid is about 100 liters per hour to about 3500 liters per hour.

In embodiments, the method further includes measuring a value related to a property of the produced fluid, measuring a value related to a property of the treated produced fluid, or both; and communicating one or more measured values to a controller; wherein the controller is designed and adapted to respond to one or more communicated values by manipulating a rate of the side stream flow.

In embodiments, an elution device is operably situated on or above the surface of the earth, or is substantially situated on or above the surface of the earth. In embodiments, an elution device is mounted on a support, wherein the support is situated on or above the surface of the earth or substantially on or above the surface of the earth. In embodiments the support is or includes a component of a completion string, such as the production tubing or a landing nipple placed at the wellhead, or another part of the wellhead infrastructure, such as a production manifold, a production flow line, an oil/water transportation pipeline, or a produced fluids processing vessel; and/or two or more of these, and/or combinations of any of these. In other embodiments, the support is integral to the elution device and is appended thereto and configured to provide a desired placement of the elution device on or above the surface of the earth.

In addition to being situated on or above the surface of the earth, the elution device of the passive elution system is operably situated proximal to the wellhead of a producing wellbore, and configured to passively receive or obtain a side stream of a produced fluid therefrom as the produced fluid flows upwards from within the wellbore to reach the wellhead area located at or near the surface of the earth. The conduit of the passive elution system is fluidly connected, at a location at or above the surface of the earth, to a source of produced fluid flowing from the wellbore; and configured to passively receive a side stream flow of the produced fluid, direct the side stream to provide an eluting contact with the treatment material of the elution device to form a treated produced fluid flow, and direct the treated produced fluid flow into the wellbore of the subterranean reservoir.

Accordingly, the passive elution systems do not require external or applied sources of power to obtain operability. That is, the passive elution systems operate by directing a fluid flow, and do not require external or applied sources of power to cause or direct fluid flow through the passive elution system. Instead, the passive elution systems are designed and configured to passively receive a produced fluid flow from a wellbore, direct the produced fluid flow into an eluting contact with a treatment material to form a treated produced fluid flow, and direct the treated produced fluid flow into the wellbore.

In embodiments one or more components of the passive elution systems are provided as a mobile elution kit. In embodiments, a mobile elution kit includes an elution device having a top and a bottom and defining an interior volume therebetween, further wherein the interior volume defines an inlet and an outlet, the inlet situated on or proximal to the top of the elution device and appended by a first connector, the outlet situated on or proximal to the bottom of the elution device and appended by a second connector, wherein the interior volume comprises a treatment material; a first conduit having first conduit first end and first conduit second end, wherein first conduit first end is appended by first mated connector for mating with the first connector of the elution device to form a first sealed fluid connection, and wherein first conduit second end is appended by a third connector, wherein the third connector is adapted and configured to obtain a fluid connection with a flow of produced fluid from a production tube of a wellbore; and a second conduit having second conduit first end and second conduit second end, wherein second conduit first end appended by second mated connector for mating with the second connector of the elution device to form a second sealed fluid connection, and wherein second conduit second end is appended by a fourth connector, wherein the fourth connector is configured to obtain a fluid communication with tubing that is capable of directing a fluid flow directly into the wellbore. In some such embodiments, the first connector and the first mated connector are a first rapid connection pair; and the second connector and second mated connector are a second rapid connection pair.

In embodiments, a mobile elution kit is assembled to form a passive elution system. In embodiments a mobile elution kit obtains one or more use cycles, where one use cycle includes the steps of a) assembling a mobile elution kit to form a passive elution system in fluid contact with a wellbore; b) treatment of the wellbore by allowing an eluting contact of a produced water from the wellbore with a treatment material disposed within the elution device of the passive elution system; and c) disassembly of the passive elution system and reformation of the mobile elution kit. In some embodiments, the mobile elution kit is transported between any one or more use cycles. In embodiments, an elution kit is transported using a street vehicle such as a pickup truck or a sedan.

Although the present disclosure provides references to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.

As used herein, the terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “and” and “the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

As used herein, the term “optional” or “optionally” means that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not.

As used herein, the term “about” modifying, for example, the quantity of an ingredient in a composition, concentration, volume, process temperature, process time, yield, flow rate, pressure, and like values, and ranges thereof, employed in describing the embodiments of the disclosure, refers to variation in the numerical quantity that can occur, for example, through typical measuring and handling procedures used for making compounds, compositions, concentrates or use formulations; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of starting materials or ingredients used to carry out the methods, and like proximate considerations. The term “about” also encompasses amounts that differ due to aging of a formulation with a particular initial concentration or mixture, and amounts that differ due to mixing or processing a formulation with a particular initial concentration or mixture. Where modified by the term “about” the claims appended hereto include equivalents to these quantities. Further, where “about” is employed to describe a range of values, for example “about 1 to 5” the recitation means “1 to 5”, “about 1 to about 5”, “1 to about 5” and “about 1 to 5” unless specifically limited by context.

As used herein, the word “substantially” modifying, for example, the type or quantity of an ingredient in a composition, a property, a measurable quantity, a method, a position, a value, or a range, employed in describing the embodiments of the disclosure, refers to a variation that does not affect the overall recited composition, property, quantity, method, position, value, or range thereof in a manner that negates an intended composition, property, quantity, method, position, value, or range. Examples of intended properties include, solely by way of non-limiting examples thereof, flexibility, partition coefficient, rate, solubility, temperature, and the like; intended values include thickness, yield, weight, concentration, and the like. The effect on methods that are modified by “substantially” include the effects caused by variations in type or amount of materials used in a process, variability in machine settings, the effects of ambient conditions on a process, and the like wherein the manner or degree of the effect does not negate one or more intended properties or results; and like proximate considerations. Where modified by the term “substantially” the claims appended hereto include equivalents to these types and amounts of materials.

In first embodiments of the passive elution systems herein, the elution device comprises, consists essentially of, or consists of a containment defining an interior volume having an outlet therefrom, wherein the elution device interior volume encloses and includes a treatment material; and the outlet of the elution device is defined on or near the gravitational bottom thereof during operation of the passive elution system and/or when the elution device is mounted on a support. The elution device outlet is in fluid communication with a conduit configured to provide an eluting contact of the treatment material with a produced fluid flow at the outlet or proximal to the outlet. Accordingly, in first embodiments herein, upon establishing fluid communication between the conduit and a produced fluid flow, the flow of produced fluid is received by the conduit and is directed toward the elution device; the produced fluid flow contacts the treatment material at the outlet or proximal to the outlet of the elution device in an eluting contact to form a treated produced fluid flow; and the treated produced fluid flow is directed through the conduit and is dispensed into a wellbore of the subterranean reservoir.

shows one example of a passive elution system of first embodiments. In, producing wellboreincludes well casingdisposed beneath the surface of the earth, where the surface of the earth is represented by dashed line E. Well casingdefines well annulus. During production, a produced fluidgathers within well annulusand is directed by production tubingto a point at or above the surface of the earth E, and toward a processing facilitywhere it is processed to provide one or more useful hydrocarbon products. Passive elution systemis fluidly connected to production tubingat side stream takeoff. Side stream takeoffis a point along production tubingthat is at or above the surface of the earth E. In embodiments, side stream takeoffis located at or proximal to the wellhead, that is, near the end of wellborelocated at or near the surface of the earth E.

As shown in, a “main” stream of produced fluidflows from wellborethrough production tubingand toward a processing facility, in the direction shown by the solid arrows. A side stream of produced fluid′ is obtained at side stream takeoff. Side stream takeoffis a fluid connection between production tubingand side stream tubingat a first endthereof. In embodiments, side stream takeoffis an opening defined in production tubing. In embodiments side stream takeofffurther includes one or more fittings or additional infrastructure necessary to complete a fluid connection between production tubingand first endof side stream tubing.

Side stream tubingis an annular conduit such as a pipe or tube that is formed from rubber, plastic, metal, or a combination of these materials, further as selected by the operator. Side stream tubingincludes an inner diameter that is less than the inner diameter of the production tubing. In embodiments, side stream tubingincludes an inner diameter that is selected by the operator to provide a flow rate of side stream′ that is suitable for the eluting contact, as discussed below. In embodiments, side stream tubinghas an inner diameter of about 1 mm to about 20 cm, or about 3 mm to about 20 cm, or about 5 mm to about 20 cm, or about 1 cm to about 20 cm, or about 2 cm to about 20 cm, or about 2 cm to about 20 cm, or about 3 cm to about 20 cm, or about 4 cm to about 20 cm, or about 5 cm to about 20 cm, or about 7 cm to about 20 cm, or about 9 cm to about 20 cm, or about 10 cm to about 20 cm, or about 12 cm to about 20 cm, or about 14 cm to about 20 cm, or about 16 cm to about 20 cm, or about 18 cm to about 20 cm, or about 1 mm to about 18 cm, or about 1 mm to about 16 cm, or about 1 mm to about 14 cm, or about 1 mm to about 12 cm, or about 1 mm to about 10 cm, or about 1 mm to about 8 cm, or about 1 mm to about 6 cm, or about 1 mm to about 4 cm, or about 1 mm to about 3 cm, or about 1 mm to about 2 cm, or about 1 mm to about 1 cm, or about 1 mm to about 5 mm, or about 1 cm to about 2 cm, or about 2 cm to about 3 cm, or about 3 cm to about 4 cm, or about 4 cm to about 6 cm, or about 6 cm to about 8 cm, or about 8 cm to about 10 cm, or about 10 cm to about 12 cm, or about 12 cm to about 14 cm, or about 14 cm to about 16 cm, or about 16 cm to about 18 cm, or about 5 mm to about about 3 cm, or about 1 mm to about 5 mm, or about 5 mm to about 1 cm, or about 1 cm to about 10 cm, or about 5 cm to about 20 cm. In embodiments side stream tubingis flexible plastic or rubber tubing such as Tygon tubing, Teflon® tubing, or Viton® tubing (available from distributors such as McMaster-Carr® of Santa Fe Springs, CA).

In the passive elution systemof, side stream valveis disposed between side stream takeoffand side stream tubingfirst endto provide an adjusted flow of side stream′ to enter side stream tubing, further wherein the direction of flow of side stream′ is indicated inby dashed arrows. Side stream valveis operable to adjust the flow of side stream′ received by side stream tubing. Accordingly, side stream valvemay be open to allow a flow, or closed prevent a flow; or may be adjustable to partially obstruct a flow. Thus, in embodiments, side stream valveis configured to provide control of the rate of flow of produced fluid′ into side stream tubing. In one or more such embodiments, side stream valvemay be manipulated by an operator to decrease or increase the flow of side stream′ into side stream tubingas needed.

In other first embodiments of the passive elution system similar the passive elution systemof, there is no side stream valve disposed between side stream takeoffand first endof side stream tubing.

Accordingly, in the passive elution systemof, the flow of side stream′ into and through side stream tubingis caused by and maintained by the fluid communication of side stream tubingwith produced fluid moving upwards through production tubing. Side stream′ is thereby caused to flow through side stream tubingin the direction shown by the dashed arrows, from first endto second endof side stream tubing. The flow of the side stream′ may be further adjusted, controlled, or stopped by manipulating side stream valveto provide a selected flow rate of produced fluid into and through side stream tubing.

Further as shown in, elution deviceis a containment defining an interior volumehaving an outlettherefrom, wherein outletis in fluid communication with side stream tubingat a location between first endand second end. Elution devicecontains a treatment materialdisposed within interior volume.

In embodiments, the elution device has an overall cuboid shape, that is, a cubic or a rectangular parallelepiped shape. In other embodiments, the elution device has an overall cylindrical shape, or a funnel type shape, or a combination of a cylindrical shape with a funnel shape portion. Since the elution device is disposed substantially above ground level, it may be generally visible and so decorative shape or other decorative or camouflaging features are employed in some embodiments associated with the elution device, the passive elution system, or portions thereof.

Elution devicefurther includes elution assemblagedisposed between outletand side stream tubing. Elution assemblagefacilitates the eluting contact between the treatment materialand the side stream′. In the embodiment shown in, elution devicefurther defines an access openingto the interior volumethereof, and a removable capthat is designed and arranged to cover opening. In some embodiments capis designed and arranged to seal interior volumefrom the surrounding atmosphere and/or prevent pressure equilibration of the interior volumewith the environment external to passive elution systemduring operation thereof. Access openingprovides access to interior volumeof elution devicefor addition of replacement treatment material, cleaning, and/or other interventions.

In other first embodiments of the passive elution system similar the passive elution systemof, elution devicehas no access opening or cap; in such embodiments elution deviceis a single-use cartridge that is pre-loaded with a treatment materialand is capable of being removably attached to side stream tubingto provide eluting contact with side stream′. In some such embodiments, the single-use cartridges may be returned to the supplier after the pre-loaded treatment material is depleted from the interior volume thereof due to eluting contact as described herein. In embodiments, the single-use cartridges are refilled by the supplier or recycled.

Further as shown in, second endof side stream tubingis located proximal to or within producing wellboreand arranged to dispense treated side streaminto the well annulusdefined by the well casing. Accordingly, second endof side stream tubingis located near the surface of the earth, at the surface of the earth, or below the surface of the earth; and proximal to or disposed within well annulus.